From 5fcbbae9bb60647ad30c7de8855932c7d6988789 Mon Sep 17 00:00:00 2001
From: Aaron LI <aly@aaronly.me>
Date: Wed, 9 Jan 2019 11:45:53 +0800
Subject: Check whether the mount point is already mounted

If the target mount point is already mounted (e.g., legacy from previous
incomplete dfly-update run), just exit with an error.
---
 dfly-update | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/dfly-update b/dfly-update
index 74bd11e..9233f1c 100755
--- a/dfly-update
+++ b/dfly-update
@@ -121,14 +121,19 @@ error() {
     exit ${ec}
 }
 
-# Mount the downloaded image (IMG file)
+# Mount the specified system image file
 #
 # mount_image(imgfile, mntpnt)
 #
 mount_image() {
     local imgfile="$1"
     local mntpnt="$2"
-    local vn
+    local dev vn
+
+    dev=$(df | awk '$NF == "'${mntpnt}'" { print $1 }')
+    [ -z "${dev}" ] ||
+        error ${EC_MOUNT} "${dev} already mounted at ${mntpnt}"
+
     [ -d "${mntpnt}" ] || mkdir "${mntpnt}"
     vn=$(vnconfig -c vn ${imgfile}) || exit ${EC_VN}
     mount -r /dev/${vn}s2a ${mntpnt} || exit ${EC_MOUNT}
-- 
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